A detailed white paper – designed to put the UK on the front foot in the troubled talks – is now not expected to appear until after a crunch EU summit at the end of June.

The document was due to be published before the two-day Brussels summit, starting on June 28, but Ms May’s spokesman refused to say that timetable would be met.

“I’ve not put a timeframe on it, other than we will bring it forward as soon as possible,” he said.

Downing Street did insist the UK would be “fully prepared” for leaving the EU without a deal, after The Sunday Times revealed civil servants had warned of a “Doomsday Brexit” that would create shortages of medicine, fuel and food.

Her spokesman said Ms May still believed that “no deal is better than a bad deal” and that a “significant amount of work” had been done to make sure the UK could cope without a Brexit agreement.